In this year-end holiday season, it is timely to reflect on American exceptionalism. Although this phrase is much abused in partisan polemics, it should not be discarded. The United States does continue to differ from most other developed democratic countries. And the heart of that difference is religion. The durability of American religious belief refutes the once-canonical thesis that modernization and secularization necessarily go hand in hand.This is all the more remarkable because our Founders drafted a deliberately secular constitution. In 20 quietly revolutionary words, Article VI declares that “[N]o religious Test shall ever be required as a Qualification to any Office or public Trust under the United States.” Consistent with that prohibition, newly elected officials—from the president on down—may choose either to “swear” (that is, to take a religious oath) or simply to “affirm” their loyalty to the Constitution.In 1789, this secular national constitution perched uneasily atop a Christian population residing in states the majority of which had established an official religion. These establishments have disappeared. But despite the enormous growth in the nation’s diversity over the past 225 years, Christian conviction remains pervasive.If you doubt this, take a look at the survey the Pew Research Center released without much fanfare two weeks ago. Among its principal findings: 73% of U.S. adults believe that Jesus was born to a virgin; 81%, that the baby Jesus was laid in a manger; 75%, that wise men guided by a star brought gifts of gold, frankincense and myrrh; and 74%, that an angel announced the birth of Jesus to shepherds. Fully 65% of Americans believe all four of these elements of the Christmas story, while only 14% believe none of them.Although Republicans are more likely to espouse these beliefs than are Democrats and Independents, each group endorses them by a two-thirds majority or more. As expected, conservatives are more likely to espouse them than are moderates and liberals. But here again, majorities of each group endorse each belief. Among liberals, 54% profess a belief in the virgin birth.What about the growth of secular thought in young Americans? As the Pew report dryly notes, there “is little sign of a consistent generation gap on these questions.” That’s an understatement. Seventy percent of adults age 18 to 29 believe that Jesus was born to a virgin; 69% that an angel announced his birth; 80% that he was laid in a manger; and 74% that the wise men made their gift-laden trek.To be sure, the most-educated Americans are less likely to profess belief in the Christmas story. But even among adults with postgraduate degrees, 53% affirm the virgin birth of Jesus, with comparable or larger majorities for the story’s other elements.These public beliefs have constitutional consequences. When it comes to church and state, many Americans are soft rather than strict separationists. When asked whether religious symbols like Christian nativity scenes should be permitted on government property, 44% said yes, whether or not the symbols of other religions are present. An additional 28% said that Christian symbols would be acceptable only if accompanied by symbols of other faiths. Only 20% took the position that no religious symbols should be allowed.Democrats should pay careful attention to these findings. In reaction to the excesses of the religious right in recent decades, many secularists and strict separationists took refuge in the Democratic Party. Their voices are important. But if the party takes its bearings only from their concerns, it risks serious misjudgment.Many Americans believe that religion has a legitimate if limited role in public life—including politics. Many Americans believe that it is wrong—not always, but usually—for laws and regulations to coerce individuals contrary to their conscientious beliefs. As Democrats pursue new policies in areas from health care to equal rights, they should work hard to minimize their intrusion on these convictions.This will not be easy. According to the Public Religion Research Institute 2014 American Values Survey, the country is split down the middle. Forty-six percent of Americans are more worried about “the government interfering with the ability of people to freely practice their religion” than they are about “religious groups trying to pass laws that force their beliefs on others,” while 46% of Americans feel the reverse. Each group offers strong arguments and poignant anecdotes. A political party that wants to build a durable majority should listen carefully to both sides and seek policies that acknowledge the legitimacy of their concerns.In this era of hyperpolarized politics, we are tempted to believe that everything right is found in our preferred party—and everything wrong in the other. It would improve the content of our policies as well as the tone of our politics to recognize that many issues are not like that. The relationship between religion and public life would be a good place to start.